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Title: Site-specific probing of charge transfer dynamics in organic photovoltaics

We report the site-specific probing of charge-transfer dynamics in a prototype system for organic photovoltaics (OPVs) by picosecond time-resolved X-ray photoelectron spectroscopy. A layered system consisting of approximately two monolayers of C{sub 60} deposited on top of a thin film of Copper-Phthalocyanine (CuPC) is excited by an optical pump pulse and the induced electronic dynamics are probed with 590 eV X-ray pulses. Charge transfer from the electron donor (CuPC) to the acceptor (C{sub 60}) and subsequent charge carrier dynamics are monitored by recording the time-dependent C 1s core level photoemission spectrum of the system. The arrival of electrons in the C{sub 60} layer is readily observed as a completely reversible, transient shift of the C{sub 60} associated C 1s core level, while the C 1s level of the CuPC remains unchanged. The capability to probe charge transfer and recombination dynamics in OPV assemblies directly in the time domain and from the perspective of well-defined domains is expected to open additional pathways to better understand and optimize the performance of this emerging technology.
Authors:
;  [1] ; ; ; ;  [2] ;  [3] ;  [1] ;  [4] ;  [5]
  1. Center for Free-Electron Laser Science/DESY, Notkestraße 85, D-22607 Hamburg (Germany)
  2. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  3. ALS, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  4. (United States)
  5. (Germany)
Publication Date:
OSTI Identifier:
22398765
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APPROXIMATIONS; BINDING ENERGY; CHARGE CARRIERS; COPPER COMPLEXES; ELECTRONS; EV RANGE; FULLERENES; LAYERS; PHOTOEMISSION; PHOTOVOLTAIC EFFECT; PHTHALOCYANINES; RECOMBINATION; THIN FILMS; TIME DEPENDENCE; TIME RESOLUTION; TRANSIENTS; VALENCE; X RADIATION; X-RAY PHOTOELECTRON SPECTROSCOPY